The present invention relates to a machine for digging and inverting crops, and in particular, a machine for digging peanuts and depositing the peanut plant in a windrow so that the peanuts pods are positioned on top of the foliage.
The raising and harvesting of peanuts includes numerous problems which, if not resolved properly, can result in significant hardship for the farmer. Unlike many crops, peanuts have a very short harvest window in which the peanuts may be harvested while obtaining close to the maximum yield. If the peanuts are harvested too early, a considerable amount of the crop will be immature and unusable. If the peanuts are harvested too late, many of the peanuts will have rotted, and the effective yield will be decreased.
While the exact harvest window varies by the type of peanut, a typical harvest time for a peanut is 145 days, with the harvest window being plus or minus 4 days. This narrow window requires that farmers harvest the peanuts as rapidly as possible, once within the window, in order to avoid the risk that the harvest will not be completed within the window due to bad weather and other problems. Those familiar with large peanut farms will appreciate that it can take several days of nonstop work to harvest the peanuts. If bad weather or other conditions prevent harvesting for a month, for example, the loss of yield will be about 40 percent. Repeated loses of such a nature can easily drive a farmer out of business.
An additional problem faced by peanut farmers is that there are four major types of peanuts, each of which has different harvesting characteristics which must be considered. Runner type peanuts are so called because the peanut plants have long branches which extend along the ground. Runner type peanuts are known for their high yields and are thus popular with farmers.
In contrast to the long branches of the Runner type peanut, the foliage of the Valencia type of peanut is what is commonly referred to as bunch type foliage. With bunch type peanuts, the foliage extends above the ground more vertically than horizontally. The Valencia type peanut is known for the large number of peanuts per pod, and for having a weak connection which holds the peanut pod to the remainder of the plant, commonly referred to as the peg.
Another type of peanut is the Spanish type. The Spanish type peanut have decumbent foliage, which is foliage having characteristics between that of the more vertical bunch type and the more horizontal runner type. Spanish type peanuts are known for their unique flavor.
Yet another type of peanut is the Virginia. The Virginia is decumbent to runner type in foliage and is known for producing high yields of large individual peanuts. Because of the different characteristics of the various types of peanuts, i.e. their foliage type and the strength of their pegs, it is difficult to design a single harvesting machine which can efficiently harvest the different types of peanuts without causing significant amounts of harvesting loss with any particular type.
Yet another problem with harvesting peanuts is that of aflatoxin. Aflatoxin is a mold which grows on peanuts when the internal moisture is between 22% and 40% for more than three days. Aflatoxin is lethal to humans if ingested. Therefore, Federal regulations strictly limit use of peanuts having a detectable amount of aflatoxin contained thereon.
To prevent losses due to aflatoxin, and to improve the flavor of several types of peanuts, the peanut pods are left to dry or cure in the sun. This is typically done by turning the peanut plant over when the peanut pods are pulled from the ground. The peanut pods are left resting on the foliage until they have dried to a desired moisture content, and are then collected using a combine.
Because the peanut pods are of greater density than the attached foliage, there is a tendency for the peanut pods to stay on the bottom during harvesting. Thus, it is necessary to mechanically turn the plant over so that the foliage comes to rest on the bottom.
To accomplish the proper placement of the peanut pod several harvesting machines have been developed. One such machine, shown in FIG. 1A, has a cutting blade 20 which travels several inches below the surface of the ground in order to uproot the peanut plants. Revolving conical drums 24, each with a plurality of fingers 28 attached thereto, are disposed directionally behind the cutting blade 20. The revolving drums 24 revolve in a direction opposite the forward direction of movement. In other words, the drums 24 rotate opposite the direction of the wheels of the tractor 32 to which they are attached.
After the roots of the peanut plant below the pod are sheared off by the cutting blade 20, the peanut plant is pulled over one of the revolving drums 24. As the peanut plant is pulled over the revolving drums 24, soil is knocked from around the peanut pod, and the peanut plant is inverted so that the plants come to rest in a windrow with the pods on top of the foliage.
Two primary disadvantages with the machine described are the speed at which the machine operates and the amount of the harvest loss, i.e. the amount of peanuts which are lost during harvesting procedures. A typical peanut inverter operates at between 2.5 and 5 miles per hour, and most typically about 3 miles per hour. While many machines will travel above this speed, the amount of pods lost as the peanut plants are inverted increases significantly as the speed is increased. Additionally, the machines often have loss levels which are significant enough to cost the farmer large sums of money.
Another approach to digging peanut plants is shown in FIG. 1B. The machine 40 has a cutter blade 44 which shears the peanut plant's roots below the pods, in a similar manner to that discussed above. The soil and peanut plants are then moved onto a conveyer belt 46 formed of a plurality of knocker bars 48 with spikes 52 disposed thereon. As the vines are carried up the conveyer belt 46 by the knocker bars 48, they are agitated to cause the soil to separate from the pods and fall between the knocker bars forming the conveyer belt.
Once at the top of the conveyer belt, the peanut plants fall onto a revolving inverter 56. The peanut plants are then passed along rigid guide bars 60 so as to form an inverted windrow.
The primary disadvantage with such an embodiment is that the machine must be moved rather slowly, i.e. about 3 miles per hour, to avoid excessive loss of the peanuts. If higher speeds are obtained, the agitation is increased to remove the soil in less time. However, this also causes a significant increase in the loss of peanut pods.
Yet another attempt to more efficiently harvest peanut plants is shown in FIG. 1C. The machine 70 has a plurality of augers 74 which rotate as the tractor (the wheels of which are shown at 76) is driven along the peanut plants. A cutting edge 78 rotates about each auger 74 and lifts the peanut plants into a pair of guides 82 which extend along the augers. The peanut plant is typically placed in the auger so that the peanuts are disposed on a side of the guides 82 opposite the auger 74, and so that the foliage remains in contact with the auger. As the auger 78 rotates, the foliage, and thus the remainder of the plant, is carried along the guides, and eventually left in an inverted windrow.
The primary disadvantage with such an arrangement is, once again, the speed at which the machine can harvest peanuts without sustaining substantial losses. If run too fast, numerous peanuts will be lost. Running the machine slow enough to harvest most of the peanuts, however, risks a delay in harvest due to bad weather or other interferences.
Thus there is a need for a crop inverter which will dig and place peanut plants in a windrow wherein the peanut plants are inverted while traveling at a relatively high rate of speed, and without a substantial loss of peanut pods.